In MS, the coating around nerve fibres (called myelin) is damaged,
causing a range of symptoms.

Around 100,000 people in the UK have MS. It's normally diagnosed in
people between the ages of 20 and 40, and affects almost three times as
many women as men.

Once diagnosed, MS stays with you for life, but treatments and
specialists can help you to manage the symptoms. We don't know the
cause and we haven't yet found a cure, but research is progressing fast.

A substance called myelin protects the nerve fibres in the central
nervous system, which helps messages travel quickly and smoothly between
the brain and the rest of the body. In MS, your immune system,
which normally helps to fight off infections, mistakes myelin for a
foreign body and attacks it. This damages the myelin and strips it off
the nerve fibres, either partially or completely, leaving scars known as
lesions or plaques.

This damage disrupts messages travelling along nerve fibres – they can
slow down, become distorted, or not get through at all.

As well as myelin loss, there can also sometimes be damage to the actual
nerve fibres. It is this nerve damage that causes the accumulation of
disability that can occur over time.

As the central nervous system links all bodily activities, many
different types of symptoms can appear in MS.

The specific symptoms that appear depend upon which part of your central
nervous system is affected and the job of the damaged nerve.